Electronic devices such as cellular phones, pagers, radios, hearing aids, headsets, barcode scanners, digital cameras, etc. are designed with enclosures having small openings located over an acoustic transducer (such as a bell, speaker, microphone, buzzer, loudspeaker, etc.) to allow sound transmission. Protective acoustic covers are placed over openings to protect the transducer from damage from dust and water intrusion.
Known protective acoustic covers include non-porous films and micro-porous membranes, such as expanded PTFE (ePTFE). Protective acoustic covers are also described in U.S. Pat. Nos. 6,512,834 and 5,828,012. Some such covers may be commercially available as Part Numbers: GAW 324, GAW 325 from W.L. Gore & Associates, Inc.
A protective cover can transmit sound in two ways: the first is by allowing sound waves to pass through it, known as a resistive protective cover; the second is by vibrating to create sound waves, known as a vibroacoustic, or reactive, protective cover.
To preserve acoustic performance of transducers, protective acoustic covers must provide minimal sound attenuation while offering high resistance to water intrusion and protection from deep immersion in water or other liquids. Further, it may be desirable to have a protective acoustic cover with enables SWB (Super Wide Band) HD (high definition) Voice call. A vibroacoustic protective cover made using the expanded PTFE composite of the present disclosure satisfies the above needs.